Emission enhancement in terbium-Ruhemann's purple complexes

Luminescent lanthanide ions such as Eu3+ and Tb3+ show emission enhancement, when complexed with Ruhemann's Purples (RPs, reaction products of ninhydrin and ninhydrin analogs with amino acids) via intramolecular energy transfer from the RP ligands (good absorbers) to the ions Eu3+ and Tb+3 (efficient emitters). The authors present the optical spectroscopic features (absorption, excitation, and emission spectra) of the complexes formed with RPs and Tb. The emission lifetimes of these complexes are also addressed.